1. Field of the Invention
This invention relates to magnets and particularly to magnets that are controlled as to field strength and plurality by mechanical twisting.
2. Description of the Prior Art
For many years the so-called Wiedemann Effect has been well known. The Wiedemann Effect is a twist produced in a wire that exhibits magnetostriction when that wire is placed in a longitudinal magnetic field and current flows through the wire. The converse or inverse of this has also been long recognized and is commonly called the Inverse Wiedemann Effect. In the Inverse Wiedemann Effect axial magnetization is produced by a magnetostrictive wire that carries current therethrough when the wire is twisted.
There have been a number of attempts to employ the effect outside of the rod as the entire magnetic field produced by the anisotropic remanence is wholly within the rod and hence is not externally apparent. However, if the rod is twisted, the direction of anisotropy will be shifted from the circular to a helical direction whereby to cause the magnetic induction to align with a new direction of anisotropy and thus have a longitudinal component. This will cause longitudinally extending magnetic flux to appear at the ends of the rod and thereby exhibit magnetism.